Valve mechanism.



. G. CHRISTIANSEN.

VALVE MBGHANISM. l APPLICATION FILED APB. 20, 1910.

y Patented Dec. 5, 1911.

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I ,4//f4//7//7//444//W UNITED sTATEs PATENT oEEIcE.

CHARLES CHBISTIANSEN, 0F GELSENKIRCHEN, GERMANY. l

VALVE MEcHANrsm.

Specification 'of Letters Patent.

Patented Dec.' 5, 1911.

Application filed April 20, 1910. Serial No. 556,617.

l specification..

My invention. relates to improvements in .valve mechanisms especially adapted for compressed air tools,l rock drills` and the like, which permit expansion of the compressed air during a definite period of the stroke of the Working piston, and therefore a delinite degree of expansionV of thecompressed air.

The object of the invention is to provide regulating mechanism in which the admission valves are surely opened and securely held in open position during the admission period and surely closed and securely held 1n closed position during the remainder of the stroke of the piston. This construction also permits the tool to be surely started, and the valves are simple in construction, and can be easily manufactured, and mounted or dismounted. Y n

With these objects in view, my invention consists in improved mechanism comprising valves at both ends of the cylinder independent of each other andV opened in the usual way by the pressure of the air during;l

the compression` period, and which valves are also subjected to a dilerential action be# tween the pressure of the opposite end of the cylinder which constantly acts on the valve, and the pressureof the adjacent end of the cylin er which is active after a port has been ope ed by the working piston.

Two examples embodying the invention have been illustrated in Figures 1 and 2, in which longitudinalsections of the cylinders are shown.

In the example shown in Fig. 1, there is a valve plunger at each end of the cylinder, eachconsisting of two sections, the sections at one marked aand b, and 'at thevother end, c and d, the sections a and c being of less diameter than the sections b and d. These valve plungers are located in bores at the ends of the cylinder communicatin therewith and extending laterally there om, each bore having sections of smaller diameter to receive sections a and c of the plungers and sections of larger diameter to receive the tion b. As the cross-sectional area of l b is larger than that of the j b is forced end of the cylinder beingl sections b vand The valve plungers are longltudinally shiftable in bores of the cylinder wall and by this 'means-the admission port e to the left hand end of the cylinder andv the admission port f to the/,right hand end of the cylinder can be opened or closed. In this example there is a space provided between the plunger sections a and b which communicates with the right vhand end of the cylinderthrough a canal g and a space between the plunger sections c andvd which v communicates with the left hand end of the cylinder `through a canal h. The space at the rear of the plunger section b communicates with the cylinder through a canal z',.

and the space at the rear of the plunger section d communicates with the cylinder through a canal lc. The position of the dischargeend of the canal 'i determines the end -of the admission period, o1' lthe be innin of the expansion period, at the le han end of the cylinder, and the position of the end of the admission period, at the right hand end of the cylinder. In therpositlon shown the valve plunger sections a ando are in their elevated positions, and they are lheld in their elevated positions by the pressure of the air. which is being admitted tol the cylinder, which pressure acts on the lower side of the plunger section a. Therefore the working piston Z is forced toward the right. In the position.. of the piston shown the discharge end of the canal is still covered by\ the piston l. At the vnext discharge end of the canal cdetermines the moment, however, the said discharge .end

will be freed from the piston Z.' Nowv high pressure air is admitted through the canal z' to the space at the rear of the plunger seg:-

t e plunger section plunger section a, the plunger downward so as to move the valve plunger section a on its seat. During the furtherv -movement 'of the piston vthe compressed air is expanded. Therefore the canal lwhich determines the beginning of the expansion'. v

may be termed the expansion canal?. The pressure at the rear of the plunger section b is the same asthat which acts on the working piston. Therefore the plunger section b holds the valve plunger, in its closed position. Before, u on the further movement of the piston Z, t e exhaust port m of the left hand end of the cylinder is` freed from the piston l, the exhaust port -n of the right hand end of the cylinder has already been closed by the piston. Therefore compression at the right hand end of the cylinder, has begun prior to the exhaust at the left hand end of the cylinder. As long as the pressure at the left hand end of the cylinder is greater than the pressure at the right hand end of the cylinder, the pressure in'the rear of the plunger section b is greater than that in front of the same. On the other hand, the pressure in the rear of the plunger section a is lless than that in front of it. As the diameter of the plunger section b is larger than that of the plunger section b is elevated and separated from the plunger section a, but the plunger section a is still forced on its seat as before. Upon the, further movement of the piston Z toward the right, the canal la is covered by the piston, and finally by the compression of the air the plunger sections c and d are elevated, so that admission of the pressure fluid begins. The plunger sections c and d remain 1n their elevated positions, until, af-

ter the return of the piston, the canal-k isl opened. At this moment the valve is closed by the plunger section d. The operations of the regulating 'mechanism are the same at the right hand end of the cylinder as at the vleft hand end thereof.

In Fig. 2, the rear end of a pressure cylinder is shown on a larger scale, which cylinder is provided with a regulating mechanism of a modified construction. The regulating member consists of a plunger comprising a plurality of sections o1, o2, o3. The middle section o2 has a larger diameter than the end sections 01 and o. The sections are guided in an air tight manner in bores of the cylinder wall. The chamber p provided above the section 08 communicates with the opposite end of the cylinder through a canal p1; the annular chamber g lprovided above they section o2 communicates with the adjacent end of the cylinder through an expansion canal 91,', and the annular chamber 7" provided below the section 02 communicates with the atmosphere through a canal r1. When the piston 1n the cylinder is in its extreme right hand position, the sections o1, 02, o3 will have been raised and the valve opened by the pressure of the air in the cylinder compressed by the piston. The sections 01, 02, o3 remain in the raised position during the first part of the return stroke of the piston to the left, because the pressure of the compressed air. admitted direct thereto, acts on the lower face of the section o1 and the rear of the valve is connected to the exhaust through the canal p1. When, however, the canal g1 is freed from the piston, the directly admitted pressure is transmitted through the said canal to the annular chamber g, and the plunger sections are moved to the closing position. The diameter of the plunger sections 01 and 03 is the same, and the cross-sectional areas of the annular chambers above and below the plunger section o2 are somewhat larger than the faces of the plunger sections 01 and o3. As the annular chamber r below the plunger section 02 is under atmospheric pressure, and the annular face above the plunger section o2 is larger than the faces of the plunger sections o1 and 03, the plunger sections o1, 02, 03, are held in the lclosing position, as long as the pressure at the right hand end of the cylinder is greater than that at the left hand end. When the pressure at the right hand end of the cylinder has decreased to atmospheric pressure by opening the exhaust port s, compression has already begun at the left hand end of the cylinder. Therefore the sections 01, 02, 03, are not held any longer on their seats by the pressure within the chamber g, but by the pressure within the chamber p.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is

1. Valve mechanism comprising -a cylinder, having an admission port near leach end, an exhaust ort between each admission port and the midlength of the cylinder, a valve for each admission port, a canal leading from each end of the cylinder to admit pressure therefrom' to the rear of the valve at the opposite end, and a canal leadingfrom the cylinder between each admission and exhaust port to admit pressure therefrom to the rear of the valve at the same end of the cylinder.

2. Valve mechanism comprising a cylinder, a lateral valve chamber at each end communicating directl with the cylinder,

A Hand divided mto sections-valve plungers `leach comprising sections.; fitting the valve chamber sections, each forward section of each plunger forming an admission valve to the cylinder, a canal leading from each 4valve chamber at the rear of one section of the plunger to the opposite end of the cylinder, and a canal leading from each valve chamber in the rear of another section of each plunger leading to the end of the cyl/'- inder with which said valve chamber communicates.

3. Valve mechanism comprising a cylinder, and a piston reciprocating therein, plunger sections of different diameters for each end of the cylinder reciprocating in corresponding lateral 'chambers communicating with the' ends of said cylinder, a sec- A chambers communicating with the ends of -the rear of a smaller section of each plunger tion of each plunger of a smaller diameter? serving as an admission valve to the cylinder, said cylinder having an exhaust portin its wall at a distance from the cylinder head,A a canal connecting the chamber at the rear of the larger section of each plunger with the adjacent end of the cylinder at a point intermediate the cylinder head and the exhaust port, and a canal connecting a chamber at with the opposite end ofV thecylinder.

4,-. Valve mechanism comprising a cylinder, and a piston reciprocating therein, a plunger for each end of the cylinder, consisting of independently movable sections of diiferent diameters and reciprocating in said cylinders, aV section of said plunger of smaller Ydiameter, servin as an admission valve to the cylinder, saidcylinder having an exhaust port in its wall at a distance from the c linder head, acanal connecting the chamger at the rear of the larger section of each plun er device with the adjacent end of the cylmder at a point intermediate the cylinder headand the exhaust port, and a 'canal connecting a chamberat the rear of a smaller section of each plunger with the opposite end of the cylinder. g; In witness whereof I have hereunto set my hand in presence of two witnesses.

. CHARLES CHRISTIAN SEN. Witnesses:

JEAN GRUND, CARL GRUND. 

